Hasumi H, Nagata E, Nakamura S
Biochem Biophys Res Commun. 1983 Jan 14;110(1):280-6. doi: 10.1016/0006-291x(83)91292-5.
Highly purified ferredoxin-NADP+ reductase from spinach leaves showed at least eight different protein bands in the electrofocused gel. All of them were catalytically active and were adsorbed on a ferredoxin-Sepharose 4B affinity column. The N-terminal amino acid sequence of the main component species was analyzed by the automatic Edman degradation method. It was found that when the reductase was stored at 4 degrees C, new protein bands appeared in isoelectric focusing and sodium dodecyl sulfate polyacrylamide gel electrophoreses, but the appearance of the bands was suppressed by the addition of a protease inhibitor, diisopropyl fluorophosphate. This indicates that the molecular heterogeneity of the reductase may result from the digestion with a protease present in spinach leaves.
从菠菜叶中高度纯化的铁氧化还原蛋白-NADP⁺还原酶在等电聚焦凝胶中显示出至少八条不同的蛋白带。所有这些蛋白带都具有催化活性，并且能吸附在铁氧化还原蛋白-琼脂糖4B亲和柱上。通过自动埃德曼降解法分析了主要组分的N端氨基酸序列。结果发现，当还原酶在4℃储存时，等电聚焦和十二烷基硫酸钠聚丙烯酰胺凝胶电泳中会出现新的蛋白带，但添加蛋白酶抑制剂二异丙基氟磷酸可抑制这些条带的出现。这表明还原酶的分子异质性可能是由菠菜叶中存在的一种蛋白酶的消化作用导致的。
